xvi PREFACE
persion, respectively. Chapter 8 focuses on the use of wavelength- and time-division
multiplexing techniques for optical networks. Code-division multiplexing is also a part
of this chapter. The use of optical solitons for fiber-optic systems is discussed in Chap-
ter 9. Coherent lightwave systems are now covered in the last chapter. More than 30%
of the material in Chapter 6–9 is new because of the rapid development of the WDM
technology over the last 5 years. The contents of the book reflect the state of the art of
lightwave transmission systems in 2001.
The primary role of this book is as a graduate-level textbook in the field ofoptical
communications. An attempt is made to include as much recent material as possible
so that students are exposed to the recent advances in this exciting field. The book can
also serve as a reference text for researchers already engaged in or wishing to enter
the field of optical fiber communications. The reference list at the end of each chapter
is more elaborate than what is common for a typical textbook. The listing of recent
research papers should be useful for researchers using this book as a reference. At
the same time, students can benefit from it if they are assigned problems requiring
reading of the original research papers. A set of problems is included at the end of
each chapter to help both the teacher and the student. Although written primarily for
graduate students, the book can also be used for an undergraduate course at the senior
level with an appropriate selection of topics. Parts of the book can be used for several
other related courses. For example, Chapter 2 can be used for a course on optical
waveguides, and Chapter 3 can be useful for a course on optoelectronics.
Many universities in the United States and elsewhere offer a course on optical com-
munications as a part of their curriculum in electrical engineering, physics, or optics. I
have taught such a course since 1989 to the graduate students of the Institute of Optics,
and this book indeed grew out of my lecture notes. I am aware that it is used as a text-
book by many instructors worldwide—a fact that gives me immense satisfaction. I am
acutely aware of a problem that is a side effect of an enlarged revised edition. How can
a teacher fit all this material in a one-semester course onoptical communications?I
have to struggle with the same question. In fact, it is impossible to cover the entire book
in one semester. The best solution is to offer a two-semester course covering Chapters
1 through 5 during the first semester, leaving the remainder for the second semester.
However, not many universities may have the luxury of offering a two-semester course
on optical communications. The book can be used for a one-semester course provided
that the instructor makes a selection of topics. For example, Chapter 3 can be skipped
if the students have taken a laser course previously. If only parts of Chapters 6 through
10 are covered to provide students a glimpse of the recent advances, the material can
fit in a single one-semester course offered either at the senior level for undergraduates
or to graduate students.
This edition of the book features a compact disk (CD) on the back cover provided
by the Optiwave Corporation. The CD contains a state-of-the art software package
suitable for designing modern lightwave systems. It also contains additional problems
for each chapter that can be solved by using the software package. Appendix E provides
more details about the software and the problems. It is my hope that the CD will help
to train the students and will prepare them better for an industrial job.
A large number of persons have contributed to this book either directly or indirectly.
It is impossible to mention all of them by name. I thank my graduate students and the